Response to ‘Improving abundance estimation by combining capture–recapture and presence–absence data: Example with a large carnivore’

A key area of research in ecological statistics involves combining data sources from multiple streams to improve population estimates. One such model attempts to integrate capture–recapture and presence–absence data to estimate the population size of Eurasian lynx in the Jura Mountains, eastern France. This model has been observed to underestimate population sizes. We conducted an extensive simulation study to evaluate the model's performance. We describe our methods for generation of simultaneous capture–recapture and presence–absence data and demonstrate that the model is flawed. Finally, we give an outline of our hypothesis on why the model underestimates population sizes. In this study, we critically evaluate the model proposed by Blanc et al. (2014) for combining capture–recapture and presence–absence data to estimate wildlife population sizes. Through extensive simulation studies, we demonstrate that this model systematically underestimates population sizes and fails to incorporate the data effectively. We highlight the necessity for rigorous evaluation of novel ecological models to avoid misleading conservation decisions and suggest that proper integration of multiple data sources remains a promising yet challenging area for future research.